If using Word 97 or above:
If you have isolated the corruption to a particular table, either:
Paste the table into Excel; delete the Word table; paste the Excel table back into Word, select the new table (Alt+Double-click), press Ctrl+Spacebar to remove the manual formatting, and reformat the table, or:
Select Table + Convert Table to Text, select the text that results, and select Table + Convert Text to Table. This has the advantage that you lose much less formatting than using the Excel method, but the disadvantage that if a corruption is stored in a paragraph mark within the table, it will remain.
If the table contains horizontally merged cells, it's best to recreate a few rows at a time – for instance, if using method (b), then after converting the table to text, select contiguous rows that have equal numbers of columns, convert them to a table, and keep doing this until you have converted all the text to individual tables (which will automatically merge themselves into a single table).
If you have isolated the corruption to a particular paragraph, select the text in the paragraph, but be careful not to select the paragraph marker (the paragraph marker is a property container, and that's where the corruption is stored). Paste into a new document. Delete the corrupt paragraph. Paste back from the new document to the old one.
You can try saving as RTF, closing Word, reopening the RTF file and saving back as a Word document. Unfortunately, Word's RTF format is similar enough to Word's native format to preserve most corruptions.
If that doesn't work, delete any Section Breaks using Find and Replace, then Select All (Ctrl+A), de-select the final paragraph mark (Shift + Left arrow), copy, and paste into a new document. Then close the corrupt document and save the new one, overwriting the old one (in that order). Finally, log out or restart your operating system before doing anything more (because document corruptions can corrupt memory).
If even that doesn't work, try saving in Word 2 format if you have this option (the Word 2 converter is no longer offered, but if you have upgraded from a previous version, you will still have it). Unfortunately, you will lose an awful lot of formatting if you do this, though.
If even that doesn't work, select File + Open, set the “Files of type” list box to “Recover Text from Any File”, and open the corrupt document. Delete the gobbledygook at the end. You'll lose all of your formatting leaving only the text.
Note that the “Recover Text from Any File” setting is “sticky”. In Word versions prior to 2002, you must immediately select File + Open again, change the “Files of type” setting back to “Word Document” and open another document, while you remember. If you forget, every file you open will have no formatting, and if you save it in this condition, it's gone forever. See Whenever I open a document using File Open all my formatting is gone, and there is garbage at the end).